Unit 1 - Fundamentals of algorithms

Question 1

Define the term “algorithm”

Answer 1

An algorithm is a sequence of steps that can be followed to complete a task; for example, a computer program

Question 2

Define the term “decomposition”

Answer 2

Decomposition is the breaking down of a problem into smaller sub-problems which can be broken down further until each small task is manageable

Question 3

State the advantages of decomposition

Answer 3

Advantages of decomposition are:
* The problem becomes easier to solve when it consists of a number of small modules
* Some modules can be reused in other programs which saves development time

Question 4

Define the term “abstraction”

Answer 4

Abstraction is the process of removing unnecessary detail from a problem so that you can focus on the essential components

Question 5

Define the term “variable”

Answer 5

A variable is a location in memory where you can temporarily store a value such as a string

Question 6

Define the terms “sequence”, “selection”, and “iteration”

Answer 6

• Sequence - a series of steps which are completed one after the other
• Selection - the ability to choose different paths through a program
• Iteration - repeating a part of the program

Question 7

What is this flowchart symbol?

Answer 7

Start/End - this begins and ends all flowcharts - the shape is called a terminator

Question 8

What is this flowchart symbol?

Answer 8

Arrow - this shows the relationship between the representative shapes

Question 9

What is this flowchart symbol?

Answer 9

Input/Output - this either asks the user to input information or displays information

Question 10

What is this flowchart symbol?

Answer 10

Process - maths operations and assignment of variables

Question 11

What is this flowchart symbol?

Answer 11

Decision - changes the flow of the program based on a decision

Question 12

What is this flowchart symbol?

Answer 12

Subroutine - calls a different function or procedure

Question 13

What is an “integer”?

Answer 13

An integer is a whole number

Question 14

What is a “real”?

Also known as a “float”

Answer 14

A real is a number with a decimal point

Question 15

What is a “boolean”?

Answer 15

A boolean is something which can only be true or false

Question 16

What is a “character”?

Answer 16

A character is a single alphabetic or numeric character”

(e.g. “a”, “K”, “4”, “@”, “%”, etc)

Question 17

What is a “string”?

Answer 17

A string is one or more characters enclosed in quote marks

(e.g. “I severly dislike having to study this”)

Question 18

What is “pseudocode” and why is it used?

Answer 18

Pseudocode is a structured English for describing algorithms, allowing programmers to focus on the logic of the program without being distracted by the exact syntax of the programming language

Question 19

What is meant by “linear search” and how does it work?

Answer 19

A linear search is a way of sorting a list by going through each item in sequence in the list and eliminating it until the desired item is found.

Question 20

State the advantages and disadvantages of linear search.

Answer 20

Linear search can work with any unsorted list but can take a long time if the list is very long